The tropical forest zone contains 1.76 billion ha, divided
into six ecofloristic zones: the tropical rain forests, the moist
deciduous forests, the dry zone, the very dry zone, the desert
zone and the hill and mountain forests. Table 8 presents the
regional distribution of these six categories. Ninety-six percent
of tropical forests occur in the following four formation types.

Tropical rain forests are found in areas with more than
2 500 mm of annual rainfall. They are evergreen, luxuriant and
rich in animal and plant species. More than half the world's
718.3 million ha of rain forests are located in two countries:
Brazil (41 percent) and Indonesia (13 percent). Rain forest
composition and structure vary with distance from the ocean,
distance from rivers, altitude and geographic position.

Moist deciduous forests occur in areas with an annual
rainfall of 1 000 to 2 000 mm. Forest structure varies depending
on the amount and distribution of rain, the type of soil and the
length of the dry season. Some dominant tree species may lose
their leaves towards the end of the dry season. This forest type
is generally less diverse than rain forest.

Dry zone forests are found in tropical areas receiving
between 500 and 1 000 mm of rainfall per year. They are
relatively open and include thornland, shrubland, savannah and
other short and sparse woody vegetation. Dry zone forests tend to
be fragile and are easily degraded. More than half are in Africa.
Dry forest types include oak, mesquite, piņon-juniper, maquis
and acacia.

Tropical upland forests are forests above 800 m and
include cloud forests (montane rain forests), which are shorter,
floristically simpler and more heavily laden with mosses and
lichens than lowland rain forests. Tropical upland species are
similar to temperate forest species. The upland zone covers the
Himalayas, parts of Myanmar, Thailand and Viet Nam, the highlands
of Mexico, the Andes and the highlands of Ethiopia and mountains
around Lake Victoria.

More than 200 million people live in clearings in tropical
forests. They include groups who have lived in the same forest
for generations, often referred to as indigenous or tribal
peoples; people who have recently moved into the area, often
described as settlers or squatters; and people who live part-time
in the forest working as small-scale harvesters of forest
products." These forests contribute to food security by
providing sources of food, income, jobs, fuelwood, medicine and
construction materials. Hunting for forest wildlife provides a
significant proportion of the protein requirements of forest
dwellers and the rural poor in many countries.

Table 8: Area of tropical forest formation, 1990

Region

Total forest
area

Rain forest

Moist
deciduous

Dry deciduous

Hill and
mountain

Very dry

Desert

('000 ha)

Africa

527586

86616

251143

92527

35256

58660

3385

Asia

310597

177371

41832

41108

47163

37

3085

Latin America and Caribbean

918116

454309

294306

44944

121895

1045

1616

TOTAL

1756299

718297

587281

178579

204314

59742

8086

Source: FAO

Forests also provide important indirect services. For example,
forests surrounding towns, villages and communities offer
critical soil erosion protection on hillsides and near streams.
Deforestation in nearby watersheds may lead to flooding of
lowland areas, displacement of populations and reductions in food
production, as happened recently in Thailand and
Madagascar."

Tropical deforestation. The rates, causes and
effects of deforestation differ greatly from one country or
region to another. These differences are due to population
density and growth rates, the extent and quality of forest
resources, levels and rates of development, the structure of
property rights and cultural systems. Recent estimates suggest
that nearly two-thirds of tropical deforestation worldwide is due
to farmers clearing land for agriculture." Table 9 provides
data on deforestation rates by region for the four major forest
zones. As FAO points out in its recent book on sustainable forest
management (footnote 5, p. 252), tropical forests are not being
destroyed for trivial reasons. They are being cleared to provide
expanding populations with land for food and cash crops. Many
growing economies depend on wood products as a source of jobs,
income, tax revenue and export earnings. Logging concessions and
industrial roundwood production, from which sawnwood, panels and
pulp and paper originate, provide these opportunities.

The largest losses of forest area are taking place in the
tropical moist deciduous forests, the zone best suited for human
settlement. In the decade 1981 to 1990, an estimated 61 million
ha were deforested, which is more than 10 percent of the
remaining moist deciduous area. The proportion of moist deciduous
area still forested is 46 percent (only 29 percent in Asia). In
contrast, 76 percent of the world's rain forest zone is still
covered in forest. During the past decade, the total area of rain
forest cut was 46 million ha.

TABLE 9A: Forest cover and deforestation in the tropical
zone

Region

Total land
area

Forest area
1980

Forest area
1990

Annual change
in area 1981-90

Annual rate
of change

(million ha)

(%)

Africa

2 236

568

527

-4.1

-0.7

Asia

892

350

311

-3.9

-1.2

Latin America

1 650

992

918

-7.4

-0.8

WORLD TOTAL

4 778

1 910

1 756

-15.4

-0.8

TABLE 9B: Deforestation in the tropical rain forest zone

Region

Total land area of zone

Total
forested area 1990

Annual
deforestation 1981-90

(million ha)

(million ha)

(% of zone)

(million ha)

(% of zone)

Africa

118.5

86.6

73

0.5

0.5

Asia

306.0

177.4

58

2.2

1.1

Latin America

522.6

454.3

87

1.9

0.4

WORLD TOTAL

947.1

718.3

76

4.6

0.6

TABLE 9C: Deforestation in the moist deciduous zone

Region

Total land area of zone

Total
forested area 1990

Annual
deforestation 1981-90

(million ha)

(million ha)

(% of zone)

(million ha)

(% of zone)

Africa

653.6

251.1

38

2.2

0.9

Asia

144.6

41.8

29

0.7

1.5

Latin America

491.0

294.3

60

3.2

1.0

WORLD TOTAL

1 289.2

587.2

46

6.1

1.0

TABLE 9D: Deforestation in the dry and very dry zones

Region

Total land area of zone

Total
forested area 1990

Annual
deforestation 1981-90

(million ha)

million ha)

(% of zone)

(million ha)

(% of zone)

Africa

823.1

151.2

18

1.1

0.7

Asia

280.6

41.1

15

0.5

1.1

Latin America

145.4

46.0

32

0.6

1.3

World total

1 249.1

238.3

19

2.2

0.9

TABLE 9E: Deforestation in the tropical upland formations

Region

Total land area of zone

Total
forested area 1990

Annual
deforestation 1981-90

(million ha)

(million ha)

(% of zone)

(million ha)

(% of zone)

Africa

169.2

35.3

21

0.3

0.8

Asia

102.6

47.2

46

0.6

1.2

Latin America

429.1

121.9

28

1.6

1.2

World total

700.9

204.4

29

2.5

1.1

Note: Table 9A gives figures on forest cover in the tropical
zone as a whole, including forests growing in zones not regarded
as zones of natural forest growth, such as deserts or alpine
areas. The data for Tables 9B to 9E are restricted to the zones
of natural forest growth. The sums of the figures in these tables
do not necessarily agree with Table 9A. Source: FAO, op. cit.,
footnote 5, p. 252.

The available data on tree plantation areas suggest that the
100 million ha of plantations in the world provide for 7 to 10
percent of the world's present commercial wood consumption."
An additional 14 million ha of rubber and coconut oil palm
plantations are not included in the area of forest plantations.
These are mainly in Asia and the wood obtained from them is
increasingly important.

Statistics on plantations must be treated with caution because
some reports use figures based on the accumulated area planted
without any deductions for the areas felled. in other cases,
figures are based simply on the numbers of seedlings distributed
to farmers or communities and not on the numbers planted or
surviving. On the other hand, the figures may omit the numbers of
trees planted by farmers from their own seedlings.

Plantations cannot provide the full range of goods and
services supplied by a natural forest. They are tree crops,
analogous to agricultural crops, with a simplified ecology of one
or, at most, a few species usually chosen for their yield and
ease of management. The primary purpose of most plantations is to
produce wood or other products quickly and cheaply. Their role,
which is a highly valuable one, complements national or global
forestry management strategies.

Plantations can be highly productive. The increment of timber
from a tropical plantation may be 30 ml per hectare compared with
2 to 8 ml per hectare from a managed natural forest. Annual
yields of up to 70 ml per hectare have been attained in Brazil
from clones of hybrids of eucalyptus species. Such figures must
be treated with caution, however (see Box 12). Experience shows
that the yields assumed at the planning stage of many plantations
are overestimated, often by a factor of two or more .20 Tree
plantations that are well planned and managed can be highly
productive and are ideal for supporting large-scale wood
industries.

In tropical countries, the net area of plantations (taking
into account the estimated survival rates) is estimated to be
about 30 million ha, counting industrial and community
plantations but not including trees planted by farmers themselves
on their own lands. The area dedicated to plantations is growing
at an average rate of around 2.6 million ha per year; about half
of this area is in communally owned plantations.

A recent review of tropical plantations concluded that
planning is generally poor, particularly for vital issues such as
matching species and site. The study also noted that plantation
projects are often designed in haste, with scant attention paid
to important issues because of time and financial constraints.

Temperate countries also have numerous examples of plantations
that have failed or sites that have been degraded because large
blocks of single-species plantations have been established,
unsuitable species have been introduced and even-aged plantations
have been planted. Case-studies describe improperly managed
temperate plantations as degrading key natural habitats,
increasing soil erosion, modifying local hydrological cycles,
intensifying pest and disease attacks and elevating levels of
agrochemical pollution.

In the developing countries, further development of plantation
forestry is constrained by the shortage of land. With expanding
farming populations using all the unforested land for food
production, the areas available for plantations are becoming
increasingly restricted. The experience of the past two decades
demonstrates that degraded or "waste" land may be the
only resource available to the landless poor. There are, however,
large areas where the natural forest has been badly degraded or
where soil fertility has been lost through overcultivation, which
could be used for plantations.

BOX 12: MALAYSIA'S COMPENSATORY PLANTATION
PROGRAMME

Malaysia has a long history of experience with tree
plantations. To meet projected timber requirements, the country
established teak plantations in its northern peninsula in the
late 1950s. A decade later, fast-growing tropical pine
plantations were planted to provide longfibre pulp for an
expanding pulp and paper industry. Prime lowland natural forest
was cleared to plant Pinus caribaea, P. merkusii and Araucaria
spp.

In the 1980s, a number of factors prompted policy-makers to
expand plantations. First, revised projections made it clear that
natural forests alone could not entirely meet the growing demand
for logs. The initial growth rates and production estimates of
the country's selective management system proved to be
overoptimistic. Second, three-decades of agricultural development
had reduced much of Malaysia's natural production forests to less
productive and harder to manage hilly areas. Third,
over-harvesting in many areas resulted in a significant backlog
of secondary forest in need of silvicultural treatment and
rehabilitation.

The government responded by establishing the Compensatory
Forest Plantation Programme. As the name suggests, this
large-scale programme was intended to compensate for the
declining timber production from Malaysia's natural forests by
establishing 188 000 ha of fast-growing, utility-grade tree
plantations. As development programmes converted natural forests
to agricultural and other uses, the timber would be used by an
expanding wood processing industry. An important objective of the
compensatory plantation programme was to maintain timber
production at levels that could support the country's wood
processing capacity.

In the early 1980s, international donors promoted fast-growing
species such as Acacia mangium, Gmelina arborea and Paraserianthes
flacataria as a means of relieving pressure on natural
forests. The Malaysian Government accepted funding to plant these
species even though the performance of the principal species to
be planted, Acacia mangium, was largely unproven in
Malaysia. Nor was this species well established in domestic or
international markets.

Over time, problems with the performance of A. mangium
became evident. Although the tree grows rapidly, it has poor
form, is vulnerable to heartrot and is not a reliable source of
utility-grade timber. To date, its wood appears to be more
suitable for wood chips, a much lower-value end use. As a result,
the government has halted the Compensatory Forest Plantation
Programme.